Epidermal growth factor, and its human homologue urogastrone (EGF/URO), are secreted by the gut-associated salivary and Brunner's glands. Recombinant EGF/URO is a powerful stimulator of cell proliferation and differentiation in the rodent and neonatal human intestine. But EGF/URO is not absorbed from the adult gut and has no action when given through the gut lumen; thus the role of secreted EGF/URO is unknown. We now report that ulceration of the epithelium anywhere in the human gastrointestinal tract induces the development of a novel cell lineage from gastrointestinal stem cells. This lineage initially appears as a bud from the base of intestinal crypts, adjacent to the ulcer, and grows locally as a tubule, ramifying to form a new small gland, and ultimately emerges onto the mucosal surface. The lineage produces neutral mucin, shows a unique lectin-binding profile and immunophenotype, is nonproliferative, and contains and secretes abundant immunoreactive EGF/URO. We propose that all gastrointestinal stem cells can produce this cell lineage after mucosal ulceration, secreting EGF/URO to stimulate cell proliferation, regeneration and ulcer healing. This cell lineage is very commonly associated with gastrointestinal mucosal ulceration, and we conclude that a principal in vivo role for EGF/URO is to stimulate ulcer healing throughout the gut through induction of this cell lineage in the adjacent mucosa.

Recessive dystrophic epidermolysis bullosa (RDEB) is a severe inherited skin-blistering disorder caused by mutations in the COL7A1 gene that lead to reduced type-VII collagen and defective anchoring fibrils at the dermal-epidermal junction (DEJ). Presently there are no effective treatments for this disorder. Recent mouse studies have shown that intradermal injections of normal human fibroblasts can generate new human type-VII collagen and anchoring fibrils at the DEJ. To assess potential clinical benefits in humans, we gave single intradermal injections of allogeneic fibroblasts to five subjects with RDEB. We noted increased type-VII collagen at the DEJ at 2 weeks and at 3 months following injection and increased anchoring fibrils, although none of these had normal morphology. No adverse effects, clinical or immunopathologic, were noted. We believe the major effect of allogeneic fibroblasts is to increase the recipients' own COL7A1 mRNA levels with greater deposition of mutant type-VII collagen at the DEJ and formation of additional rudimentary anchoring fibrils. Nevertheless, this mutant protein may be partially functional and capable of increasing adhesion at the DEJ. This is the first study demonstrating that intradermal injections of allogeneic fibroblasts have therapeutic potential in human subjects with RDEB.

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Objectives:Current models of clonal expansion in human Barrett’s oesophagus are based upon heterogenous, flow-purified biopsy analysis taken at multiple segment levels. Detection of identical mutation fingerprints from these biopsy samples led to the proposal that a mutated clone with a selective advantage can clonally expand to fill an entire Barrett’s segment at the expense of competing clones (selective sweep to fixation model). We aimed to assess clonality at a much higher resolution by microdissecting and genetically analysing individual crypts. The histogenesis of Barrett’s metaplasia and neo-squamous islands has never been demonstrated. We investigated the oesophageal gland squamous ducts as the source of both epithelial sub-types.Methods:Individual crypts across Barrett’s biopsy and oesophagectomy blocks were dissected. Determination of tumour suppressor gene loss of heterozygosity patterns, p16 and p53 point mutations were carried out on a crypt-by-crypt basis. Cases of contiguous neo-squamous islands and columnar metaplasia with oesophageal squamous ducts were identified. Tissues were isolated by laser capture microdissection and genetically analysed.Results:Individual crypt dissection revealed mutation patterns that were masked in whole biopsy analysis. Dissection across oesophagectomy specimens demonstrated marked clonal heterogeneity, with multiple independent clones present. We identified a p16 point mutation arising in the squamous epithelium of the oesophageal gland duct, which was also present in a contiguous metaplastic crypt, whereas neo-squamous islands arising from squamous ducts were wild-type with respect to surrounding Barrett’s dysplasia.Conclusions:By studying clonality at the crypt level we demonstrate that Barrett’s heterogeneity arises from multiple independent clones, in contrast to the selective sweep to fixation model of clonal expansion previously described. We suggest that the squamous gland ducts situated throughout the oesophagus are the source of a progenitor cell that may be susceptible to gene mutation resulting in conversion to Barrett’s metaplastic epithelium. Additionally, these data suggest that wild-type ducts may be the source of neo-squamous islands.